Field of the Invention
The present invention relates to a protective film for a polarizing plate comprising a (meth)acryl-based resin, and a polarizing plate using the same.
Description of the Background Art
A polarizing plate used in a liquid crystal display device or the like usually has a structure in which a transparent protective film is laminated on both surfaces or one surface of a polarizing film via an adhesive layer. Triacetylcellulose has previously been used widely in such a protective film for a polarizing plate, but in order to improve heat and humidity resistance and the like of the polarizing plate, use of a stretched (meth)acryl-based resin film having a low moisture permeability for the protective film has been proposed in recent years.
However, since the stretched (meth)acryl-based resin film is relatively low in adhesiveness to various surface-treatment layers which can be formed on a surface of the film, and adhesiveness to the polarizing film via an adhesive layer, there has been the following problem: the surface-treatment layer or the polarizing film is easily peeled.
As a method which can solve the problem, Japanese Patent Laying-Open No. 2009-205135 describes that an easily adhesive layer is formed on an adhesion surface to a polarizing film in a stretched (meth)acryl-based resin film using an aqueous (meth)acryl-based resin dispersion. Japanese Patent Laying-Open No. 2008-058768 describes that a coating layer including a (meth)acryl-based resin as a main component is formed on the adhesion surface.
Japanese Patent Laying-Open No. 2012-159665 describes that adhesion property between a phase retardation film and a polarizing film can be improved by setting a planar orientation coefficient of a phase retardation film surface including a norbornene-based resin, polycarbonate or triacetylcellulose to less than or equal to 0.8×10−3.